1. Field of the Invention
The present invention relates to an organic electroluminescent (hereinafter referred to as EL) element, an organic EL display, and a method of manufacturing an organic EL display.
2. Description of the Related Art
An organic EL element has a structure in which an organic layer including an emitting layer is interposed between a pair of electrodes. The emitting layer normally made of a mixture containing a host material and a dopant material. The emitting layer can be formed by vacuum evaporation as described in JP-A 2003-157973 (KOKAI), for example.
In view of increasing the degree of luminous efficiency, it is ideal to set the concentration of the dopant material at an optimum value in all the parts of the emitting layer. However, under normal circumstances, the concentration of the dopant material monotonically increases or monotonically decreases along the thickness of the emitting layer. Therefore, the concentration of the dopant material can be optimized only on a single plane that is parallel with a surface of the emitting layer. For this reason, most of organic EL elements are low in the degree of luminous efficiency.